Fish: Form and function

1. Fish:
Form and function
An LSU Museum of Natural Science presentation to
accompany the activity

2. Types and Function of fins
All Fish have fins! Each fin shape has a unique shape and
function.
Dorsal- (top fin) Helps keep the fish upright. Also used for
sudden direction changes.
Pectoral- These are the pair of side fins that help the fish move
in different directions and aids in the ability to swim and
steer. Sometimes have spines used for defense.
Dorsal fin
Pectoral fin

3. Pelvic- Located on the bottom of the fish. Most
often used as “brakes”.
Anal- used to stabilize fish
Additional fins:
Adipose- tiny fin between dorsal and caudel fins
Pelvic fin
Anal fin
Types and Function of fins

4. Caudel (Tail) fin
This fin is used to propel the fish through the
water, pick up speed, and make turns.
• Rounded caudal fin –allows for effective acceleration and
maneuvering but in general is found on fish that do not swim
long distances because of large amounts of drag
• Truncated caudal fin – straight tipped tail; allows for quick turns
and short burst of speed
• Emarginated caudal fin – has the least amount of drag; fin has
two lobes
• Forked caudal fin- 2 lobes, helps reduce turbulance
• Lunate caudal fin- tend to be fastest fishes, maintain speeds

5. Body shapes of Fish
Sagitiform – elongated tubular body layout that
is arrow shaped; allows fish to strike quickly.
(Example: gar, barracuda)
Depression – wide, flat
body shapes that all fish
to rest on the bottom.
(Example: flounder)

6. Body shapes of Fish
Fusiform: streamlined with
pointed ends - shaped like a
plane; helps to lower frictional
resistance, and allows them to
move through the water
extremely fast.
Compressiform – fish that
are laterally compressed; tall,
thin body shape that allows
fish to enter vertical crevices;
allows for quick bursts of
speed and quick turns.

7. Anguilliform – fish that are long
and skinny; these fish slither like
snakes; allows them to maneuver
into narrow openings and resist the
force of current.
Globiform – these fish are almost
round or globe-shaped.
Body shapes of Fish
Taeniform – thin ribbon like shape; good for hiding in
crevices and cracks.

8. Lateral line
Pelvic fin
Pectoral fin
Anal fin
Caudal
2nd dorsal fin
1st dorsal fin
Eye
Operculum
Mouth
Nostril

9. GyotakuGyotaku
Japanese art of fish printingJapanese art of fish printing
How it works:
1. Paint plastic fish
2. Press painted fish onto paper to make
impression. Label parts if desired.

10. Build you own ‘Franken’fishBuild you own ‘Franken’fish
Materials:
• Fish part templates
• Glue
• Crayons
• Construction paper
• Scissors
• Pencil and paper
Purpose: Students will learn about fish anatomy and
morphology by building their own fish.

11. On-line Resources
• Fish anatomy print-out
Enchanted learning-
http://www.enchantedlearning.com/subjects/fish/l
• Basic information on fish
http://www.flmnh.ufl.edu/FISH/Education/Diagrams
• Gyotaku fish